<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8">
  <title>Document</title>
  <style>
    
  </style>
</head>
<body>
  
</body>
<script>

  var str1 = "hello";
  var str3 = "hello";

  var str2 = new String("world");
  var str4 = new String("world");

  console.log(str1);
  console.log(typeof str1);
  console.log(str2);
  console.log(typeof str2);

  console.log( str1 + 1 );

  console.log( str2 + 1 );

  console.log( {} + 1 );
  
  console.log( str1 === str3 );
  
  console.log( str2 === str4 );



  // var n = 10;
  // var m = new Number(20);

  // console.log( n );
  // console.log( typeof n );
  // console.log( m );
  // console.log( typeof m );

  // console.log( n+1 );
  // console.log( m+1 );
  // console.log( {}+1 );



  // var b1 = false;
  // var b2 = new Boolean(false);

  // console.log(b1);
  // console.log(typeof b1);
  // console.log(b2);
  // console.log(typeof b2);

  // console.log( b1+1 );
  // console.log( b2+1 );
  // console.log( {}+1 );

  
</script>
</html>